A wide variety of contactors currently is available for use such as the conventional plastic contactors and/or partially shielded contactors are amongst those widely used in the market.
Many of these shielding devices are constructed of relatively thin flexible sheets of metal and utilize spring contactors for making electrical contact at multiple locations to effect ground connections in various shielding arrangements.
Shielding is a founded on coaxial theory, wherein by shorting the housing to the ground pins, a virtual ground plane will be created around the signal pins to provide a good control over the impedance which is a major contributor in determining the performance of the contactor.
One commercially available contactor known as partially shielded contactors consist of three plates. The middle plate, made of conductive materials, are shorter to the ground pins thus creating a virtual ground plane that shields the signal pin at a constant impedance. The top plate and bottom plate, made of engineered plastic materials, are to hold the pins in position and prevent them from shorting to ground. In order to obtain good control over the impedance of a partially shielded contactor would be to maximize the shielding percentage by reducing the plastic materials plates so as long as it does not compromise the mechanical structures of the contactor.
It would be highly desirable to have that can be aligned with contact pads if 100% shielding is achieved. Nevertheless, the limiting factor in the currently available contactors, one is not able to achieve 100% shielding factor as the thicknesses of the plastic plates are totally dependent on the mechanical limitation and requirements of the sockets.
It would also be desirable to have such a contactor which is less susceptible to damage. To achieve such a 100% Shielding Factor, the housing must be fully made from conductive metal.
In doing so, steps and measures are taken to prevent the signal pins from being shorted to housing as this may cause improper setup and faulty device.